施肥对半干旱地区小麦产量、NO_3^-N累积和水分平衡的影响

Effects of Fertilization on Wheat Yield, NO_3^-N Accumulation and Soil Water Content in Semi-Arid Area of China

依据长武站长期田间试验(1984～2001 年)的结果,分析了不同施肥措施条件下小麦产量、氮肥利用率、土壤水分的变化及其相互间的关系。结果表明,对照、有机肥(M)、氮肥(N)、氮磷肥(NP)、氮肥+有机肥(NM)和氮磷肥+有机肥(NPM)处理冬小麦的17 年平均产量依次为1.5、2.6、2.0、3.3、3.4 和4.0 t·ha-1;冬小麦地上部17 年累计吸收的氮量依次为509.0、854.6、781.9、1 199.8、1 067.5 和1 430.9 kg·ha-1;2001年0～300 cm 土层NO3 -N 储量依次为52.2、113.1、1 064.8、254.5、535.4 和512.1 kg·ha-1,N 处理的NO3 -N 分 - -布于0～300 cm 土层,NP、NM、NPM 处理的NO3 -N 主要分布于0～180 cm 土层。收获期0～300 cm 土层多年平均 -水分含量为CK>N>M>NP>NPM。播种期NP、NPM 处理200～300 cm 土层水分出现亏缺。施肥是黄土旱塬区土壤生产力提高、土壤深层水分亏缺和土壤NO3 -N 累积的驱动力。 -

On the basis of long-term experiment at Changwu station on the Loess Plateau, winter wheat yield, nitrogen fertilizer use efficiency, and soil water cycle under continuous wheat cropping system were investigated. For the average of wheat yield over 17 years, CK, M, N, NP, NM, and NPM treatments were 1.5, 2.6, 2.0, 3.3, 3.4, and 4.0 t·ha-1, respectively. For total N uptake by wheat after 17 years, CK, M, N, NP, NM, and NPM treatments were 509.0, 854.6, 781.9, 1 199.8, 1 067.5, and 1 430.9 kg·ha-1, respectively. For NO3 -N level in 0-300 cm in 2001, CK, M, N, NP, NM, and NPM treatments were 52.2, 113.1, 1064.8, 254.5, 535.4, - and 512.1 kg·ha-1, respectively. Fertilizer N use efficiency ranged from 15% to 36% among fertilizer N treatments. For NO3 -N - accumulation, N treatment was high in depth of 0-300 cm, NP, NM, and NPM treatments were high in 0-180 cm. Soil water content at harvest follows this order: CK>N>M>NP>NPM. For NP, NPM treatments, subsoil water deficit produced at planting. Fertilization significantly (P<0.05) enhanced crop yield, increased soil productivity led to subsoil water deficit, the soil-water deficit retarded NO3 -N movement down and accumulated in the soil profiles. Fertilization is a common drive to increase crop yield, subsoil - water deficit and nitrate accumulation in the soil profiles of continuous wheat cropping system on the Loess Plateau.